import { equals } from 'is-kit';

// Object.is semantics are preserved
equals(NaN)(NaN); // true

// Literal guards narrow discriminated unions
const isDone = equals('done' as const);
// isDone: (value: unknown) => value is 'done'

type Status = 'draft' | 'in-progress' | 'done';

function isFinished(status: Status) {
  if (isDone(status)) {
    // Narrowed to the literal type 'done' inside this branch
    return true;
  }
  return false;
}

isFinished('draft'); // false
isFinished('done'); // true

import { equalsBy, equalsKey, isString } from 'is-kit';

// Build a comparator in two steps for clarity
const lengthOfString = equalsBy(isString)((s) => s.length);
const isLength3 = lengthOfString(3 as const);
isLength3('foo'); // true

// Key-based equality guard
const hasId1 = equalsKey('id', 1 as const);
hasId1({ id: 1 }); // true